The present application relates to dust control during particle handling at a well site.
Subterranean wells (e.g., hydrocarbon producing wells, water producing wells, and injection wells) are often stimulated by hydraulic fracturing treatments where the fractures are formed in a subterranean formation and held open with particles (also referred as “proppant”) to enhance fluid conductivity through the formation. Often, many tons of particles are used in a fracturing operation. Such particles are also used during gravel packing operations to control sand production in a subterranean formation during production, for example. As used herein, the term “particle” refers collectively to proppant particles, gravel particles, and any other solid particles that may be used in a subterranean formation operation.
When preparing particles at the surface of the well site for use in an operation, large amounts of dust can be created by the movement of particles, thereby creating inhalation hazards. For example, a common particle (e.g., proppant particle, gravel particle, and the like) is sand, which produces silica dust that is associated with a lung disease known as silicosis, or Potter's rot. Silicosis is a type of pneumoconiosis that manifests as inflammation and scarring in forms of nodular lesions in the upper lobes of the lungs.
A particle-handling apparatus a piece of particle-handling equipment that can produce dust. Generally, a hopper is used to receive particles from bags or another storage/transportation system. The hopper feeds a conveyance (e.g., a screw auger) that conveys the particles to a mixer, which is generally where water and other additives (e.g., viscosifiers, surfactants, friction reducers, resins, tackifiers, and the like) may be mixed with the particles, such as to form the proppant slurry when the particles are proppant particles. The particle-handling apparatus is typically configured such that the particles drop from the conveyance into the mixer in an open-air arrangement. Such a configuration allows workers to monitor the contents of the mixer and add materials thereto. However, this configuration also forms a significant amount of dust, which, when coupled with worker proximity during operation, creates a substantial exposure risk.
Dust control is very rarely used with a particle-handling apparatus, despite the significant amount of dust that is typically formed. When dust control measures are used, they are most commonly in the form of a covering, like a tarp, to enclose the portion of the apparatus where the particles fall from the conveyance to the mixer (e.g., at the tub inlet). In some instances, a vacuum system with a hose under the covering is also used to capture the dust. While this reduces the dust exposure risk to workers, the covering can also eliminate the workers' access to the mixer.